blob: fc1c0c613e2896d37b842c4e8e84edc8191aa5e2
1 | /* |
2 | * This file is part of FFmpeg. |
3 | * |
4 | * FFmpeg is free software; you can redistribute it and/or |
5 | * modify it under the terms of the GNU Lesser General Public |
6 | * License as published by the Free Software Foundation; either |
7 | * version 2.1 of the License, or (at your option) any later version. |
8 | * |
9 | * FFmpeg is distributed in the hope that it will be useful, |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
12 | * Lesser General Public License for more details. |
13 | * |
14 | * You should have received a copy of the GNU Lesser General Public |
15 | * License along with FFmpeg; if not, write to the Free Software |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
17 | */ |
18 | |
19 | #ifndef AVFILTER_HERMITE_H |
20 | #define AVFILTER_HERMITE_H |
21 | |
22 | static inline double hermite_interpolation(double x, double x0, double x1, |
23 | double p0, double p1, |
24 | double m0, double m1) |
25 | { |
26 | double width = x1 - x0; |
27 | double t = (x - x0) / width; |
28 | double t2, t3; |
29 | double ct0, ct1, ct2, ct3; |
30 | |
31 | m0 *= width; |
32 | m1 *= width; |
33 | |
34 | t2 = t*t; |
35 | t3 = t2*t; |
36 | ct0 = p0; |
37 | ct1 = m0; |
38 | |
39 | ct2 = -3 * p0 - 2 * m0 + 3 * p1 - m1; |
40 | ct3 = 2 * p0 + m0 - 2 * p1 + m1; |
41 | |
42 | return ct3 * t3 + ct2 * t2 + ct1 * t + ct0; |
43 | } |
44 | |
45 | #endif /* AVFILTER_HERMITE_H */ |
46 |